Moinmoin

A Wiki, written in Python. It uses the filesystem for storage of pages (as opposed to a database), employs caching to speed up page serving, has support for serving multiple wikis through a single server process. MoinMoin also does page locking, to prevent concurrent edit smashing.

For ideological reasons, it does not support forums: it is a resolutely wikish wiki.

MoinMoin can use Apache, Twisted or its own Python built-in web server. Since it is written in Python, it runs under Windows, MacOS and Linux, plus other more exotic platforms.

I find it attractive for its simplicity. Not reccomended for large complex sites, which would probably work better with a proper database-backed CMS, such us our own beloved Everything2 or the MediaWiki system used by Wikipedia.